1. Field of the Invention
The present invention relates to a light source driving device, a light scanning device and an image forming apparatus, more specifically, to a light source driving device that drives a light source, a light scanning device that scans a surface to be scanned and an image forming apparatus including the light scanning device.
2. Description of the Related Art
As an image forming apparatus that forms an image using Carlson's process, for example, an image forming apparatus in which a surface of a rotating photoconductive drum is scanned by light beams so that a latent image is formed on the surface of the rotating photoconductive drum is known. The image forming apparatus is configured to form an image by fixing a toner image obtained by visualizing the latent image to paper as a recording medium. In recent years, the image forming apparatus of this kind has often been used in simplified printing as an on demand printing system. Requests for images of higher density and image output of higher speed are further increasing.
Thereby, in order to simultaneously obtain an image of higher density and image output of higher speed, an image forming apparatus, which scans a photoconductive drum at once with a plurality of light beams using a multi-beam light source is proposed. An image forming apparatus of this kind deflects a bundle of light beams emitted from a surface emitting type laser having a plurality of light emitting parts so that it is possible to scan the photoconductive drum using a plurality of light beams at once.
A surface emitting type laser, for example, VCSEL (vertical cavity surface emitting laser) or the like is used in the image forming apparatus. A plurality of light emitting parts can easily be two-dimensionally arranged in one element, and as a result, the respective light emitting parts are influenced by heat generation thereof as well as heat generation from the peripheral light emitting parts and there is a problem in that light emitting properties change with time.
Thereby, an image forming apparatus including a mechanism to maintain the temperature of a light source at a constant or a light scanning device including a light source in which light emitting parts are disposed such that cross-talk does not become a problem is proposed (for example, see JP2006-202846A and JP2001-272615A). However, in these apparatuses or devices, a part such as a heat releasing plate or the like is required, and the degree of freedom of design of the optical system becomes small so that there is a problem in that the device gives rise to higher cost.